Brodmann area 9

Abstract: Context Predisposition to alcoholism is likely an interaction between genetic and environmental factors that confer vulnerability and protection. Alcoholic subjects have low levels of dopamine D 2 receptors in striatum, and increasing D 2 receptor levels in laboratory animals reduces alcohol consumption. Objectives To test whether high levels of D 2 receptors may be protective against alcoholism and whether this is mediated by their modulation of activity in orbitofrontal cortex and cingulate gyrus (regions involved in salience attribution, emotional reactivity, and inhibitory control). Design Research (nonalcoholic subjects with a family history of alcoholism) and comparison (nonalcoholic subjects with a negative family history) sample. Setting Outpatient setting. Participants Fifteen nonalcoholic subjects who had an alcoholic father and at least 2 other first- or second-degree relatives who were alcoholics (family-positive group) and 16 nonalcoholic controls with no family history of alcoholism (family-negative group). Main Outcome Measures Results of positron emission tomography with raclopride C 11 to assess D 2 receptors and with fludeoxyglucose F 18 to assess brain glucose metabolism (marker of brain function). Personality measures were obtained with the Multidimensional Personality Questionnaire. Results Availability of D 2 receptors was significantly higher in caudate and ventral striatum in family-positive than family-negative subjects. In family-positive but not family-negative subjects, striatal D 2 receptors were associated with metabolism in anterior cingulate (Brodmann area 24/25) and orbitofrontal (Brodmann area 11) and prefrontal (Brodmann area 9/10) cortices, and with personality scores of positive emotionality. Conclusions The higher-than-normal D 2 receptor availability in nonalcoholic members of alcoholic families supports the hypothesis that high levels of D 2 receptors may protect against alcoholism. The significant associations between D 2 receptors and metabolism in frontal regions involved with emotional reactivity and executive control suggest that high levels of D 2 receptors could protect against alcoholism by regulating circuits involved in inhibiting behavioral responses and in controlling emotions.

Abstract: Urban upbringing has consistently been associated with schizophrenia, but which specific environmental exposures are reflected by this epidemiological observation and how they impact the developing brain to increase risk is largely unknown. On the basis of prior observations of abnormal functional brain processing of social stress in urban-born humans and preclinical evidence for enduring structural brain effects of early social stress, we investigated a possible morphological correlate of urban upbringing in human brain. In a sample of 110 healthy subjects studied with voxel-based morphometry, we detected a strong inverse correlation between early-life urbanicity and gray matter (GM) volume in the right dorsolateral prefrontal cortex (DLPFC, Brodmann area 9). Furthermore, we detected a negative correlation of early-life urbanicity and GM volumes in the perigenual anterior cingulate cortex (pACC) in men only. Previous work has linked volume reductions in the DLPFC to the exposure to psychosocial stress, including stressful experiences in early life. Besides, anatomical and functional alterations of this region have been identified in schizophrenic patients and high-risk populations. Previous data linking functional hyperactivation of pACC during social stress to urban upbringing suggest that the present interaction effect in brain structure might contribute to an increased risk for schizophrenia in males brought up in cities. Taken together, our results suggest a neural mechanism by which early-life urbanicity could impact brain architecture to increase the risk for schizophrenia.

Abstract: We investigated the neural correlates of idiomatic sentence processing using event-related functional magnetic resonance imaging. Twenty-two healthy subjects were presented with 62 literal sentences and 62 idiomatic sentences, each followed by a picture and were required to judge whether the sentence matched the picture or not. A common network of cortical activity was engaged by both conditions, with the nonliteral task eliciting overall greater activation, both in terms of magnitude and spatial extent. The network that was specifically activated by the nonliteral condition involved the left temporal cortex, the left superior medial frontal gyrus (Brodmann area 9), and the left inferior frontal gyrus (IFG). Activations were also present in the right superior and middle temporal gyri and temporal pole and in the right IFG. In contrast, literal sentences selectively activated the left inferior parietal lobule and the right supramarginal gyrus. An analysis of effective connectivity indicated that the medial prefrontal area significantly increased the connection between frontotemporal areas bilaterally during idiomatic processing. Overall, the present findings indicate a crucial role of the prefrontal cortex in idiom comprehension, which could reflect the selection between alternative sentence meanings.